Exfoliative cytology of tracheobronchial adenoid cystic carcinoma

Bronchial cytology of pulmonary adenoid cystic carcinoma - A multi-institute series with emphasis on immunocytochemistry

BACKGROUND

Pulmonary adenoid cystic carcinoma (AdCC) is a central and superficial primary lung neoplasm, well-suited for sampling by bronchial cytology. This study aims to review the cytologic features of pulmonary AdCC on bronchial cytology, and to report an experience of applying immunocytochemistry on this rare entity.

METHODS

A multi-institute review of bronchial cytology specimens from histologically proven pulmonary AdCCs was performed. Published cases of bronchial cytology of pulmonary AdCC were reviewed. The cytologic features and immunocytochemical profile for pulmonary AdCC was summarized and compared with pertinent differentials.

RESULTS

A total of 16 specimens from eight patients were retrieved. The initial cytologic diagnoses were negative (n = 7), atypia (n = 6), suspicious (n = 2) and AdCC (n = 1). Retrospective review showed eight bronchial cytology specimens (including five cases of atypia) with tumor cells present. The tumor cells displayed small basaloid nuclei with occasional small nucleoli, mild nuclear atypia, and scanty cytoplasm. Architectural patterns observed included clusters, tubules, solid sheets, three-dimensional balls, papillary-like fronds, and complex cribriform structures. Basement-membrane-like material, free or associated with tumor cells, were seen in all cases. Immunocytochemistry was performed in one specimen. MYB was positive. TTF-1, synaptophysin and chromogranin were negative. Epithelial and basal markers demonstrated a dual cell population. Literature review yielded 28 cases. Cytologic features described were similar except for cytoplasmic vacuolation in one case.

CONCLUSION

Basement membrane-like material is specific for AdCC. MYB positivity, TTF-1 and neuroendocrine marker negativity, support a diagnosis of AdCC. Other immunocytochemistry and cytologic features overlap significantly with adenocarcinoma and small cell carcinoma of lung.

Tracheal Adenoid Cystic Carcinoma Presented with Chronic Asthma Diagnosed by Bronchial Washing Cytology

Adenoid cystic carcinoma is a tumor that mainly arises from salivary glands and is present rarely in airways with nonspecific symptoms. Diagnosis based on bronchial washing cytology is rarely reported because this tumor is usually lined by normal mucosa. A 35-year-old woman was referred to our center as a case of unresponsive asthma and hemoptysis for the past year. CT scan showed tracheal mass. Bronchoscopy was done followed by bronchial washing cytology and biopsy. Cytology smears revealed sheets and three-dimensional clusters of small cells, and some of them arranged around hyaline mucoid globules. Cell block and biopsy showed classic pathological findings of adenoid cystic carcinoma. Adenoid cystic carcinoma of the airways can be manifested with nonspecific symptoms and should be considered in the differential diagnosis of airway diseases and asthma. This tumor is rarely seen in the bronchial washing specimen. Characteristic cytological findings and using cell block preparation differentiate adenoid cystic carcinoma from other tumors.